What does the cryptic crossword clue "Diagram of dessert with mostly poorly mixed filling (5,4)" mean?

The wordplay uses an anagram. anagram of LOORP (synonym="LOORP") + FLAN (synonym="‘dessert’") = FLOORPLAN The answer is FLOORPLAN.

Diagram of dessert with mostly poorly mixed filling (5,4)

Guardian Cryptic #29461 | 9 Across | 2024-08-14 flower